Boichuk О. A. A criterion for the existence of the unique invariant torus of a linear extension of dynamical systems. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 59, n. 1, p. 3–13, 2007. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3288. Acesso em: 6 dec. 2025.